Search results
Results from the WOW.Com Content Network
Rickettsia rickettsii is a Gram-negative, intracellular, cocco-bacillus bacterium that was first discovered in 1902. [1] Having a reduced genome, the bacterium harvests nutrients from its host cell to carry out respiration, making it an organo-heterotroph.
Rickettsia is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci (0.1 μm in diameter), bacilli (1–4 μm long), or threads (up to about 10 μm long).
The life cycle of mites consists of egg, prelarva, larva, protonymph, deutonymph, tritonymph, and adult. The larvae, commonly referred to as chiggers, are the only ectoparasitic stage feeding on the body fluids of rodents and other opportunistic mammals. Thus, they are the only stage in the life of mites that transmit the infection.
Rickettsia typhi is a flea-borne disease organism and is widely distributed throughout the world. [18] There are two cycles in R. typhi transmission from animal reservoirs to human: a classic rat-flea-rat cycle, and a peridomestic cycle involving cats, dogs, opossums, sheep, and their fleas. [7]
They are obligate intracellular parasites, and some are notable pathogens, including Rickettsia, which causes a variety of diseases in humans, and Ehrlichia, which causes diseases in livestock. Another genus of well-known Rickettsiales is the Wolbachia , which infect about two-thirds of all arthropods and nearly all filarial nematodes. [ 2 ]
R. prowazekii is often surrounded by a protein microcapsular layer and slime layer; the natural life cycle of the bacterium generally involves a vertebrate and an invertebrate host, usually an arthropod, typically the human body louse. A form of R. prowazekii that exists in the feces of arthropods remains stably infective for months.
The tick life cycle consists of four stages: egg, larva, nymph, and adult. [9] An adult female tick can lay over a thousand eggs in her lifetime. [10] Once a tick hatches from an egg, it enters the larvae stage, where it must attach to any available host and begin feeding. After it has fed, it detaches and molts, entering the larger nymph stage.
The Rickettsiaceae are a family of bacteria.The genus Rickettsia is the most prominent genus within the family. The bacteria that eventually formed the mitochondrion (an organelle in eukaryotic cells) is believed to have originated from this family.